Effectiveness of School-Based Drug Prevention Programs for Marijuana Use

Abstract

Thirty-seven evaluations of universal drug use prevention programs implemented in American schools between grades 6 and 12 were quantitatively synthesized by coding program characteristics and calculating weighted effect sizes (WES) for marijuana use. Programs were divided into two types, Interactive and Non-Interactive, based on a combination of content and delivery method. To determine the characteristics of programs that most effectively reduce, delay or prevent marijuana use, a weighted least squares multiple regression analysis was performed using the WES of marijuana use as the dependent variable, type of program as the predictor and sample size as an additional covariate. Program type and sample size were found to be significant predictors of program effectiveness. Non-Interactive lecture-oriented prevention programs that stressed knowledge about drugs or affective development of students showed minimal reductions in marijuana use. Interactive programs that fostered the development of social competencies showed greater reductions in marijuana use. Larger implementations of both program types showed substantial decreases in effectiveness, although the larger Interactive programs were significantly superior to the larger Non-Interactive ones. The primary finding for prevention program planners is that interactive cultivation of social skills reduces marijuana use.